1. Field of the Invention
The present invention relates generally to an integrated mobile terminal device with an external display unit, and in particular, to an integrated mobile terminal device and method for controlling an external display unit.
2. Description of the Related Art
In general, an integrated mobile terminal device (also known as a “smart phone”) is comprised of a cellular phone part for performing a communication function and a personal digital assistant (PDA) part for performing a computing function.
FIG. 1 schematically illustrates a functional block diagram of a general integrated mobile terminal device. Referring to FIG. 1, the integrated mobile terminal device includes a display unit 1 for displaying the operating status of the integrated mobile terminal device, a PDA unit 2 for performing a general PDA function, a cellular phone unit 3 for carrying out a wireless communication function, and a power supply 4 for supplying an operational power source to each unit. A key entry unit, a speaker, a microphone, and the like contained generally in the integrated mobile terminal device are not shown in FIG. 1, for simplicity. The integrated mobile terminal device having the above-stated construction provides various services to users by performing both a PDA function and a cellular phone function in one device. In addition, the integrated mobile terminal device has a function of selectively switching off the PDA unit and the cellular phone unit in order to save its power.
The integrated mobile terminal device is generally divided into a bar-type and a flip-type according to its appearance. The folder-type integrated mobile terminal device with an external display unit has been developed in order to meet user's various needs. The folder-type integrated mobile terminal device includes a body, a folder, and a hinge module for mechanically connecting the body with the folder. On the external display unit is displayed display information to be frequently checked, such as an icon designating an antenna state bar, an icon designating the remaining amount of charge in a battery, and time data in a state where the folder of the integrated mobile terminal device is closed.
In controlling the external display unit of the integrated mobile terminal device, however, if either the PDA unit or the cellular phone unit, which is fully in charge of the external display unit, is switched off, the external display unit will be disabled. Moreover, if the PDA unit or the cellular phone unit is continuously in an enabled state to use the external display unit, unnecessary battery power is consumed.